PSYC 215 Chapter Notes - Chapter 7: Outer Nuclear Layer, Spectral Sensitivity, Photoisomerization

• School: Queen's University
• Department: Psychology
• Course: PSYC 215
• Professor: Niko Troje

Document Summary

Ganglion axons ganglion cells bipolar cells (horizontal cells) photoreceptors epithelium. Photoreceptors are in the outer nuclear layers. Rods contain a single synaptic cleft and cones contain several. Photon absorption depends on its direction of travel and on its frequency. Photon direction: photons arrive in a various direction, depending on where they pass through the pupil. Through the centre: parallel to the long axis. Near the edge: slight angle to the long axis. Cones have 3 different types of photopigment with different spectral sensitivities (rgb) Photon with frequency near the peak sensitivity of receptor it strike = more likely to be absorbed. Only 2/3 of photons result in a response. Photoisomerization: when a photon changes the shape of chromophore molecule: pigment molecule = opsin (protein) + chromophore (light-catching) Rods and cones differ in rhodopsin variations: photoisomerization initiates a cascade of biochemical events.